Centre for Research into Circulating Fetal Nucleic Acids, Li Ka Shing Institute of Health Sciences, Department of Chemical Pathology, The Chinese University of Hong Kong, Hong Kong SAR, China.
BMJ. 2011 Jan 11;342:c7401. doi: 10.1136/bmj.c7401.
To validate the clinical efficacy and practical feasibility of massively parallel maternal plasma DNA sequencing to screen for fetal trisomy 21 among high risk pregnancies clinically indicated for amniocentesis or chorionic villus sampling.
Diagnostic accuracy validated against full karyotyping, using prospectively collected or archived maternal plasma samples.
Prenatal diagnostic units in Hong Kong, United Kingdom, and the Netherlands.
753 pregnant women at high risk for fetal trisomy 21 who underwent definitive diagnosis by full karyotyping, of whom 86 had a fetus with trisomy 21. Intervention Multiplexed massively parallel sequencing of DNA molecules in maternal plasma according to two protocols with different levels of sample throughput: 2-plex and 8-plex sequencing.
Proportion of DNA molecules that originated from chromosome 21. A trisomy 21 fetus was diagnosed when the z score for the proportion of chromosome 21 DNA molecules was >3. Diagnostic sensitivity, specificity, positive predictive value, and negative predictive value were calculated for trisomy 21 detection.
Results were available from 753 pregnancies with the 8-plex sequencing protocol and from 314 pregnancies with the 2-plex protocol. The performance of the 2-plex protocol was superior to that of the 8-plex protocol. With the 2-plex protocol, trisomy 21 fetuses were detected at 100% sensitivity and 97.9% specificity, which resulted in a positive predictive value of 96.6% and negative predictive value of 100%. The 8-plex protocol detected 79.1% of the trisomy 21 fetuses and 98.9% specificity, giving a positive predictive value of 91.9% and negative predictive value of 96.9%.
Multiplexed maternal plasma DNA sequencing analysis could be used to rule out fetal trisomy 21 among high risk pregnancies. If referrals for amniocentesis or chorionic villus sampling were based on the sequencing test results, about 98% of the invasive diagnostic procedures could be avoided.
验证大规模平行母血浆 DNA 测序在临床上对羊水穿刺或绒毛取样有指征的高危妊娠筛查 21 三体的临床疗效和实际可行性。
采用前瞻性收集或存档的母血浆样本，对全基因组测序进行诊断准确性验证。
香港、英国和荷兰的产前诊断单位。
753 名高危孕妇进行 21 三体全基因组测序，其中 86 名胎儿为 21 三体。
根据两种不同样本通量的方案对母血浆中的 DNA 分子进行多重平行测序：2 重测序和 8 重测序。
源自 21 号染色体的 DNA 分子的比例。当源自 21 号染色体的 DNA 分子的 Z 分数>3 时，诊断为 21 三体胎儿。计算 21 三体检测的诊断敏感性、特异性、阳性预测值和阴性预测值。
8 重测序方案可提供 753 例妊娠结果，2 重测序方案可提供 314 例妊娠结果。2 重测序方案的性能优于 8 重测序方案。使用 2 重测序方案，21 三体胎儿的检出率为 100%的敏感性和 97.9%的特异性，阳性预测值为 96.6%，阴性预测值为 100%。8 重测序方案检测到 79.1%的 21 三体胎儿，特异性为 98.9%，阳性预测值为 91.9%，阴性预测值为 96.9%。
多重母血浆 DNA 测序分析可用于排除高危妊娠 21 三体。如果将羊水穿刺或绒毛取样的转诊基于测序试验结果，约 98%的侵入性诊断程序可被避免。
